Tractor switch



March 8, 1949. w. A. LEE

TRACTOR swITtiH Filed May'l1, 1945 lllllllll I IN V EN TOR.

Patented Mar. 8, 1949 UNITED STATES PATENT OFFICE TRACTOR SWITCH William A. Lee, Goodland, Ind. Application May 11, 1945, Serial No. 593,282

6 Claims. 1

This present invention relates to a device for stopping a tractor as soon as the person on the seat gets off the same or is thrown off, to prevent injury or death to the person by the implement pulled by the tractor.

The main object of the invention is the construction of a device including an incomplete electrical path from the ignition switch to the ground provided by the frame of the tractor and also including means controlled by the position of the seat occupied by the rider for completing this path when the former leaves the seat.

With these objects and other objects in view, as will become apparent throughout the course of the following description, the invention consists in certain novel construction, combination and arrangement of parts as will hereinafter be more specifically pointed out and claimed.

In the accompanying drawings, wherein for the purpose of illustration is shown a preferred embodiment of my invention, and wherein like reference characters designate like parts throughout:

Fig. l is a side view of the embodying my invention;

Fig. 2 is an enlarged longitudinal diametrical section of the cylinder and plunger forming a part of the embodiment.

In the drawings in which like reference characters indicate like or similar parts numeral 2 denotes the seat of a tractor hinged thereto and urged by a spring to a raised and tilted position. The hinge and spring is not shown. To the bottom surface of the seat which is shown as occupied by the operator and in a depressed position, is secured a ring 3 to which the upper end of a downwardly extending coil spring 4 is fastened. The lower end of the spring is secured to the top link 5 of a downwardly extending chain 6 the bottom link 1 of which is interlinked with an eye 8 of insulating material formed on the top of a plunger rod 9 of metallic material. The plunger carries at the lower end a metallic piston H] which consists of an upper frusto-conical part II and a lower cylindrical part [2.

At the bottom surface of the piston and surrounding the axis thereof is an insulating piece I 3 which insulates the ring l4 secured to the piston from the latter. The upper end of a vertically disposed spring I5 is attached to the ring while the lower end of this spring is attached to a ring I6 fastened to the central portion of the upper bottom surface of a metallic cup-shaped bottom cap H which is attached by a screw l8 or other entire assembly suitable fastening means to the top surface of a supporting plate I!) forming a conventional part of a tractor or secured thereto for this purpose.

The flange bottom cap is interiorly threaded for engagement with the lower threaded end portion of a metallic cylinder 20 within which the piston is slidably arranged. The upper end portion of the cylinder is also exteriorly threaded'for engagement with the interior threads formed on the flange of top portion 2| having the shape of an inverted cup and intended to keep out rain and dust.

A hemispherical shell 22 intended to keep out moisture and opening downwardly has a central opening 23. Into this opening extends the upper end of a tube 24 of insulating material intended to prevent a short circuit. To eifect a rigid connection with the shell the tube has near its upper end and within a shell a flange 25 which is welded or otherwise secured to the inner surface of the latter. The insulating tube encloses and is secured to the plunger rod and extends through a central aperture 26 in the flat portion of the previously described top cover 2| of the cylinder and below the top cover through a conical contact lining 21 electrically connected to the metallic cylinder 20. The space between the bottom surface of the top cover, the inner surface of the cylinder and the top surface of the conical lining is filled with insulating material 28. Below the bottom edge of the conical lining extends a cylindrical lining 29 of insulating material down to the bottom of the cylinder. The piston has sliding contact with the inner surface of this lining.

Through the top end portion of the plunger extends a bolt 30 carrying on its threaded part a pair of nuts 3| between which a wire 32 is clamped leading to the shut-ofi switch of the tractor with a magneto (not shown). Other tractors could be stopped by running wires to each spark plug.

While the rider is on the seat, the same is depressed, the spring depending therefrom is only stressed by its own weight and the weight of the chain beneath it and the plunger is held by the lower spring in the position of Fig. 2 with a considerable gap existing between the conical piston surface and the complementary contact surface of the conical lining. The hemispherical shell abuts against the upper circular edge of the top cover and functions as a limit stop.

As soon as the rider leaves voluntarily or involuntarily the seat, the latter is tilted upward by its spring (not shown) and exerts a pull on the upper spring, the chain and piston rod and overcomes the resistance of the lower spring with the result that the piston rises until its conical surface is in electrical contact with the interior conical surface of the lining.

Thereby a branch conductor from the ignition switch to the ground is completed, presenting a path of least resistance to the ignition current. The ignition ceases and the tractor is stopped.

When the tractor operator reoccupies his seat, the upward pulling force on the plunger ceases and the latter is retracted by the lower spring to the position of Fig. 2 in which there is a considerable gap between the piston and contact lining, so that the ignition circuit can perform its intended function.

While I have described and illustrated the details of the preferred. embodiment of my invention, it is to be understood that the construction hereinbefore set forth is intended merely as an illustration, not as a limitation of my invention as many obvious changes are possible without in any manner departing from the spirit and scope of my invention as defined in the appended claims.

What I claim and desire to secure by Letters Patent is:

1. In an ignition circuit interrupter for tractors or the like, an electrical conductor member adapted to be suspended from a spring supported tractor seat and extending into a normally unoccupied space therebeneath and adapted to be connected to the ignition circuit of the tractor, an electrical conductor member grounded on the tractor frame and disposed in circuit closing engagement with said first mentioned electrical conductor member when the tractor seat is in an unoccupied, elevated position, for shunting the electric circuit of the ignition to the ground on the frame to interrupt the normal ignition circuit, and said first mentioned electrical conductor member being displaceable downwardly and out of engagement with the second mentioned electrical conductor member to interrupt the circuit therebetween when the tractor seat is depressed.

2. An ignition circuit interrupter as in claim 1, said first mentioned electrical conductor member including a contractile spring for resisting the upward movement thereof relatively to the last mentioned electrical conductor member.

3. An ignition circuit interrupter as in claim 1, said last mentioned electrical conductor member including a cylinder having an electrical insulated portion in which a portion of the first mentioned electrical conductor member is reciprocally disposed and normally retained out of circuit closing relationship with the last mentioned electrical conductor member when the tractor seat is depressed.

4:. An ignition circuit interrupter as in claim 1, and spring means for normally urging the first mentioned electrical conductor member downwardly and out of engagement with the last mentioned electrical conductor member.

5. An ignition circuit interrupter as in claim 1, said first mentioned electrical conductor member including a contractile spring for limiting the upward movement thereof relatively to the last mentioned electrical conductor member, and spring means for normally urging the first mentioned electrical conductor member downwardly and out of engagement with the last mentioned electrical conductor member.

6. An ignition circuit interrupting switch, comprising an electrical conductor adapted to be connected to an ignition circuit and suspended from above by a yieldable support, and a second electrical conductor adapted to be secured to a ground for the ignition circuit and normally disposed in circuit closing engagement with the first mentioned electrical conductor, said first mentioned electrical conductor being slidably connected to the second electrical conductor for downward sliding movement relatively thereto when the yieldable support is depressed for interrupting the electrical connection between the electrical conductors.

WILLIAM A. LEE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,185,792 Hansen June 6, 1916 1,513,664 Williamson Oct. 28, 1924 1,956,978 Nafziger May 1, 1934 2,359,254 Silver Sept. 26, 1944 

